This is a double-blind, multicenter crossover study to compare the safety and efficacy of Ultrase MT12 to placebo in the treatment of steatorrhea in cystic fibrosis (CF) patients with pancreatic insufficiency. This study is designed to address the hypothesis that oral pancreatic enzyme supplementation is both effective and safe in the treatment of fat malabsorption in patients with CF and exocrine pancreatic insufficiency. The three specific aims include: 1) To evaluate the efficacy of Ultrase MT12 in the treatment of steatorrhea in CF patients with a history of pancreatic enzyme insufficiency. 2) To evaluate the safety of Ultrase MT12 in CF patients with a history of pancreatic enzyme insufficiency by performing physical examination, routine hematology, routine chemistry, and by monitoring vital signs and adverse events. 3) To measure extent of protein malabsorption.